Dental and medical instruments used on successive patients in contact with saliva or other body fluids or solids must be capable of total cleaning and sterilization after each use to prevent transmission of communicable disease. Variable suction devices such as those used by dentists to remove saliva and dental debris from the mouth are particularly in need of improvement in this regard.
Typical dental aspirator heads have a rotary valve for varying suction, as for example that shown in U.S. Pat. No. 2,885,782. However these are complicated devices with many movable parts and cannot as a practical matter be disassembled after each use for cleaning and sterilization. Many cannot even be detached from their associated suction hoses.
Moreover prior art dental aspirator heads are designed to draw all material from the mouth, not only saliva but solid debris as well and the solid material is allowed to collect in a trap of the waste disposal system of the dental facility and is only periodically removed such as once each day. During the hours while solid dental debris remains in the trap it could well be the source of contamination migrating downstream into sewage systems.
Some slide valve variable suction heads are known, such as that described in U.S. Pat. No. 3,834,388 but they are incapable of trapping solids and many are almost as complicated as rotary valve forms, as for example the slide valve design disclosed in U.S. Pat. No. 4,487,600.
Disposable traps for solids in aspiration systems are of course known as such, that described in U.S. Pat. No. 4,880,411 being one example, but not in variable suction head devices and particularly in hand-held aspirator heads used in dental procedures.
The principal object of the present invention is to provide a variable suction aspirator head which is of an irreducible minimum of parts, which can easily be assembled and disassembled for complete cleaning and sterilization of those parts after each successive use, and which is capable of trapping solids in the head itself so that they are not carried downstream to pose a contamination threat.